R Tutorials
R Introduction
R Syntax
R Comments
R Variables
R DataTypes
R Numbers
R Math
R Strings
R If..else
R Operators
R While Loop
R For Loop
R Data Structures
R Vectors
R Lists
R Matrices
R data Frames
R factors
R Graphics
R Plot
R line
R Scatterplot
R Pie Charts
R Bars
R Statistics
R Statistics Intro
R Data Set
R Max and Min
R Mean Median Mode
R Percentiles
R Examples
R Compiler
Previous
R Variables
Creating Variables in R
Variables are data storage containers.
R has no variable declaration command. Variables are created when you first give value to it. To assign a value to a variable, use the <- symbol. To output (or print) a variable value, simply type in the variable name:
Example
name <- "John"
age <- 40
name # output "John"
age # output 40
From the example above, the name and age are variables, while "John" and 40 are values.
In other programming languages, it is commonly used = as a function of the function. In R, we can use both = and <- as shareholders.
However, <- is preferred in most cases because = operator can be restricted in some cases to R.
Print / Output Variables
Compared to most other programming languages, you do not need to use the function to print / extract R. Variables.
Example
name <- "John Doe"
name # auto-print the value of the name variable
However, R has a print() function available if you want to use it. This may be helpful if you are familiar with other programming languages, such as Python, which often uses the print() function to output dynamics.
Example
name <- "John Doe"
print(name) # print the value of the name variable
There are also times when you have to use print() function to generate code, for example if you work with for loops (which you will learn more about in the next chapter):
Example
for (x in 1:10) {
print(x)
}
Conclusion: It's up to you whether you want to use the print() function or not to decrypt it. However, if your code is within the R-value (for example inside the folded brackets {} as in the example above), use the print() function if you want to extract the result.
Concatenate Elements
You can also combine, or join, two or more elements, using the paste() function.
To combine both text and flexibility, R uses a comma (,):
Example
text <- "awesome"
paste("R is", text)
You can also use , to add variables to other variables:
Example
text1 <- "R is"
text2 <- "awesome"
paste(text1,
text2)
In numbers, the character + acts as a mathematical operator:
Example
num1 <- 5
num2 <- 10
num1 + num2
If you try to combine a unit of letter (text) with a number, R will give you an error:
Example
num <- 5
text <- "Some text"
num + text
Multiple Variables
R allows you to assign the same number of multiple variables in a single line:
Example
# Assign the same value to multiple variables in one line
var1 <- var2 <-
var3 <- "Orange"
# Print variable values
var1
var2
var3
Variable Names
Variables can be a shorter word (such as x and y) or a more descriptive word (age, carname, total_ volume). The rules for R changes are:
- The variable name must start with a letter and can be a combination of letters, digits, time (.) and underscore (_). If it starts with period (.), It cannot be followed by a digit.
- A different name cannot start with a number or underscore (_)
- The most sensitive variables are (age, age and AGE are three different variables)
- Reserved names cannot be used as variables (TRUE, FALSE, NULL, if ...)
Example
# Legal variable names:
myvar <- "John"
my_var <- "John"
myVar
<- "John"
MYVAR <- "John"
myvar2 <- "John"
.myvar <- "John"
# Illegal variable names:
2myvar <- "John"
my-var <- "John"
my var <- "John"
_my_var <- "John"
my_v@ar <- "John"
TRUE <- "John"
Remember that flexible words are sensitive!